Effect of harvesting stage and some drying methods on essential oil composition of basil [ocimum basilicum, L.]

ABSTRACT

An experiment was carried out in the two growing seasons [2004 and 2005] to investigate the influence of harvesting. stage and some drying methods on the composition of the basil volatile oil [Ocimum basilicum L.]. The air drying [at room temperature] and artificial drying [in oven at 40 and 60C] are the two different methods used for drying basil leaves and herb. The results showed that the moisture loss [%] was lowest of harvest stage in September and with air drying at room temperature of both herb and leaves compared with the other treatments. The contrary was observed regarding the essential oil content in the same harvest stage results in the highest essential oil content compared with the other stages of the harvest. Significant reduction in the amount of extracted volatile oil was found in the case of drying at 60C, especially, the content of volatile oil being the highest when harvested the both herb and leaves in September and dried at room temperature. Basil leaves possessed a higher oil content and the oil was richer in oxygenated compounds [1,8 cineole, linalool, methyl chavicol and eugenol] when harvested in the September and drying at room temperature or in oven at 40C